Filling a new 500gal -- noisy return

[freshwaterguy0987]

This is a new 500gal in-wall tank with a 100gal sump. I plumbed two returns, running off of a Syncra SDC 9.0 (2500 gph) and a Syncra High Flow 12.0 Pump (3200 gph).

One return line is longer than the other, and they're running off different sizes of pump. However, both are making the same loud sucking/bubbling sound, near where they terminate at the water's surface. It's coming from that 45 degree elbow. The black length is a more flexible pvc conduit, which I used for its color (because I didn't want spray paint touching the water).

Any ideas on how to quiet this down?!? Thank you in advance!

 

[Reefing Madness]

 

[freshwaterguy0987]

Thanks for the bump. I actually figured this out. Most of the sound was coming from the drains in the overflow, but because of the tanks design (acrylic with most of the top covered) it sounded like it was coming from the return pipes. Once I adjusted the overflows, most of the sound went away. What little sound was left went away after a little while (time after turning on the pumps).

 

[freshwaterguy0987]

 

[Gumbies R Us]

That is such a neat looking tank!